Transformer construction and winding



Jan. 21, 1941.

J. C. JOOST TRANSFORMER CONSTRUCTION AND WINDING Filed Nov. 3, 1938 3.95.9 Z @qj wzzya I INVENTOR j/m/ C. J'0057 ATTO NEY UNITED STATES PATENTTRANSFORMER CONSTRUCTION AND WINDING John C. Joost, New York, N. Y.,assignor to Edwards and Company, Inc., Norwalir, Conn, a corporation ofNew York Application November 3, 1938, Serial No. 238,508

15 Claims. ((31. 175-356) This invention relates to transformerconstruc- In the accompanying drawing in which is tion, moreparticularly of the low voltage and shown a preferred one of the variouspossible emrelatively small capacity type such as is used for bodimentsof the mechanical features of my inoperating low voltage devices, suchas door bells,v vention,

buzzers, relays, low voltage appliances, and the Figures 1, 2 and'3 areplan views of top, side like, from the higher voltage of a household andend members, respectively, of a winding sup- 5 lighting circuit usuallyof 110 volts, and com port or bobbin;

cerns particularly the winding and core assembly Figure 4 is aperspective view of a conductorof transformers of this generalcharacter. anchoring member;

One of the objects of this invention is to pro- Figures 5, 6 and 7 arerespectively top, front 10 vide an inexpensive, practical and reliableinsuand end elevations of the assembled winding suplating and foundationstructure for winding the port or bobbin; coil or coils and formechanically anchoring and Figures 8 and 9 are plan views ofillustrative electrically connecting terminal conductors to the forms orshapes of laminations that may be used end or ends of the winding orwindings. Another in making up the core; 5

object is to provide a coil or winding construction Figure 10 is a topplan view of the final transthat may be constructed commercially at lesscost former assembly, including the core, windings, than has heretoforebeen possible with known windi g supp t a d e i al-conductormountmethods or types of construction, and also to imings or anchoragprove the electrical and mechanical efficiency of Figure 11 is afragmentary central sectional 0 structures of this kind. Another objectis to view as seen along the in of Figure provide a construction of theabove-mentioned Similar reference characters refer to similar characterin which assembly of the various parts parts throughout the severalviews in the drawmay be inexpensively and quickly carried on and ms.

in which strength of structure and reliability of P p o b e u t on of Ceta n 25 action are achieved in a simple and effective way. e tu of yinvention, let it be su ed t Another object is to provide a core orbobbin a coil or coils are to be related to an iron core, for supportingthe coil or coils or upon which the such as, for example, the middle leg20 (Figures coil or coils may be wound, that will be simple, l0 and 11)of a transformer core 2i, illustratively inexpensive, strong, durableand well adapted to of the shell typ and made p f la nat ons 39withstand the handling accompanying quantity appropriately shaped to bepieced together, such production thereof. as the laminations 22 and 23of Figures 8 and 9,

Another object is to provide a dependable and respect y. The WindingShould be dep ndinexpensive form of mechanical anchorage of ablysupported on the middle leg 20 and well acrelatively heavy terminalconductors for electrical comm dated within the core windows 24 and 25.35 connection with windings of fine or small or frag- Insueh ca I make pa Winding Support or ile wire, and thus to reduce breakage or damagebobbin, pr fer ly u of parts of h e nsulatin course of manufacture andin course of hanlng material, like fiber, hard rubber, or the like,dling, as well as in subsequent use of the compr f a y shaped a dconformed as shown in 4Q pleted winding or device. Another object is toFigures 2 d 3 which are D1811 e s of D ts provide a simple,,strong andreliable assembly of 27 and p c e y, e Winding o bin winding and coreand of the terminal connection being preferably so constructed that twoof each or connections of the winding, and capable of of these threeparts are emp oy d i making it upbeing carried out in a rapid, efilcientand yet Th Da -S. eov re Shaped so that they simple manner in actualpractice. Other. ob may easily n inexpensively be p nch ut of 45 jectswill be in part obvious or in part pointed out Strip Sh Stock and P frably he P 28 hereinafter. which is to function as an end member is ofTh invention accordingly consi t i th fea heavier stock than the parts26 and 27 which can tures of construction, combinations of elements, beOf e S e ge or thickness.

arrangements of parts, and in the several steps The part 28 is ingeneral four-sided, though its 50 and relation and order of each of thesame to corners may be beveled or cut off, as shown, and one or more ofthe others, all as will be illusit has stamped out of it a central hole29, also tratively described herein, and the scope of the preferablyfour-sided, particularly where the application of which will beindicated in the 101- core part 20, as in the above-described type oflowing claims. transformer core, is in cross-section four-sided 55 andapproximates a square. The hole 29 is dimensioned to be slightly greaterthan the crosssection of the core and suirlciently so to accommodate thethicknesses of the parts 26 and 21 and preferably, also, another part 30of Figure 4 to be described later.

The part 28 is provided in two opposed sides of the aperture 29 withcentrally disposed preferably rectangular recesses 31! and 32, and ispreferably also pierced at appropriate points to permit the passagetherethrough of the ends of the wires of which the winding is to bemade. Thus, I may provide two relatively small holes 33 and 34, onepositioned close to the hole 29 and the other positioned near the outerperiphery of the part 28, and two holes 35, 36 which may be larger andalso appropriately positioned, for example, as indicated in Figure 3.

I In making up and assembling the bobbin, two end members 28 areemployed and they first have related to them two members 26 which areplaced so as to rest adjacent their ends against the straight orunrecessed edges 3'5, 38, respectively, of the hole 29 in the two endmembers.

The member 26 is in general wider than the length of the edge 31 or 38of the end member 28, and along its longitudinal edges it is cut away toprovide opposed pairs of recesses or notches 39, the bottoms of eachpair being spaced by the dimension equal to the length of the edge 3'!or 38, and also preferably a single pair of elongated notches 40, 40whose bottom edges are spaced from each other by preferably the samedimension.

Two members 26 may thus be passed into the holes 29 of two end members28, the latter being appropriately held spaced from each other (seeFigure the wider end portions of the members 26 being passed preferablyalong a diagonal of the holes 29; the members 26 may then be moved orswung to bring one of them against the edges 31, 31 of the holes 29 ofthe two members 28, and the other one against the edges 38 thereof,appropriate portions of the members 28 taking into and snugly fitting inthe opposed notches 39 whose width closely matches the thickness of themembers 28. In Figure 5 this relationship is clearly shown. Thisassembly may be achieved in any suitable way and if desired a mandrel(not shown) may be slid into position between the two members 26 to holdthem in spaced relation from each other and to facilitate assembly ofthe remaining parts.

The remaining parts preferably comprise two members 21, shaped as shownin Figure 2. The member 21 is generally rectangular and at its narrowends is provided with tongues 4|, 4| dimensioned to snugly fit into therecesses or notches 3|, 32 in the opposed edges of the hole 29, and inits opposed longitudinal edges is provided with tongue-like extensions42, 42 dimensioned to be snugly received in the notches 48 of themembers 26.

With two end members 26 and two side members 26 assembled asabove-described, two members 21 may now be assembled to theabove-described sub-assembly, and this may be done by first entering oneend tongue 4! into a notch 3| or 32 of one end member 28, and for thatpur-' pose a snugly fitting mandrel, as above described, is helpful; inFigure 5 I have indicated in dotted lines such an initial position of amember 21 with one end tongue 4| thus entered into a notch in theleft-hand end member 28. Then the member 21 may be swung in clockwisedirection and pressed downwardly to snap its opposed end tongue 4| intothe notch in the member 28, the parts yielding sufiiciently, even thoughthey snugly interflt, for this purpose, whence the longitudinal tongues42, 42 enter and rest in the notches 48, 49 of the two members 26. Theother member 21 may be put into place in the same way, resulting in astructure better shown in Figures 5, 6 and 7.

The resultant structure is unitary, rigid, free from play, strong, andhas its parts dependably interlocked so that all are held in place andeach contributes to maintaining rigidity of construction. The notches 39of the two members 26 hold the end members in spaced relation, members27, with their tongues 42 fitting into the notches 48 of the members 26,and in fact with the contiguous appropriately configured edges of themembers 26 and 21 in mutually overlapping relation, hold the members 28against movement toward each other while this interrelationship causesthe members 26 to hold the members 21 against movement toward eachother. The tongues 4! of the members 21, in taking into the notches 3|,32 of the end members, cause the latter to hold the members 21 againstoutward movement and thus to insure the maintenance of theabove-described mutually overlapping relationship of the contiguousedges of the members 26 and 21. Also, the end edges of the members 21 toeither side of the tongues 4| are butt-ended against the faces of themembers 28 and thus prevent the rightangled relationship between the endmembers 28 and the members 26 from being changed.

The construction is light yet very strong and the individual parts areeasily and inexpensively stamped and assembly is simple and rapid, itbeing noted that I make it possible to eliminate the use of tools orsecuring devices or other cumbersome means of fastening or securing. The

interlocking or mutual overlapping of the contiguous edges of successivemembers 26 and 21 also insures that throughout the length thereof noinward yielding takes place particularly under any tensioning ortightness of insulated wire as the latter is subsequently wound onto thebobbin and between the end members 28; the latter also are dependablyheld against movement away from each other and thus dependably resistany tendency on the part of the wire being wound to push them outwardly.

Upon the resultant bobbin and between the end members 28, the coil orcoils may now be wound. Where the device is to function in atransformer, as above described, two coils are wound on the bobbin, oneof them, the high voltage winding, usually 110 volts, being usually ofrelatively fine wire which, depending upon design and powerrequirements, may range, for example, from No. 25 to No. 40, or so. Thiswinding is preferably wound onto the bobbin first and any standard orusual practice may be employed in the winding process. One end of thewinding is preferably brought out through a hole 33 (Figures 3 and 7) inone end member, and when the required number of turns is wound, theremaining end is brought out through a hole 34 in the opposite endmember.

The low voltage winding usually comprises less delicate or fragile wireand a lesser number of turns. Either winding may be wound first andillustratively the low voltage winding may be wound on top of the highvoltage winding, again using any standard or known practices ineffecting the winding and superimposition of one winding in layers uponthe other. Being of heavier wire, the ends of the low voltage windingare brought out through an opening 35 in one end member and an opening36 in the other end member, it being noted that these ope i s are largerto accommodate the heavier wire, suitable lengths of end portions beingleft free for ultimate connection to appropriate binding posts (notshown).

The ends of the low voltage winding are brought out through theabove-described openings, but the latter are so positioned and selectedthat the wire ends come out below the lower member 26, as viewedin.Figures 6 and 7, while a similar selection is made of the smalleropenings to bring the fine and delicate ends of the high voltage windingout above the upper mem ber 26, as viewed in Figures 6 and 7.

Now one of the difficulties heretofore encountered and which myinvention effectively and dependably overcomes is the connection ofthese fine end wires to suitable and heavier terminal conductors orwires, usually heavily covered with insulation. Heretofore suchdifliculty has included not merely coping with the delicacy of theoperation but also with the mechanical obstacles presented and whichfrequently resulted in breaking of the fine wire. Having completed thestructure as thus far described, noting first that the end edges of themembers 2G are provided with notches 44 of a depth such that theirbottoms are appropriately spaced from the outer faces of the end members28 (see Figure 5), I next put into position the member 30 of Figure 4;that member is preferably made of sheet metal, is generally rectangular,and is provided with upwardly bent tongues 45 of suitable width, thenotches 44 being of a width snugly to accommodate the tongues 5.

Member 30 is slid into the hollow bobbin and brought flush up againstthe upper member 26 to the outer side of which the fine wire ends of thehigh voltage winding extend, the tongues 45 passing upwardly through thenotches 44 so that they project upwardly from the two end portions ofthe member 26, as is clearly shown in Figure 6.

Suitable lengths of heavy wire, usually No, 14, usually heavilyinsulated as is typical of 110-volt circuits, as indicated at 46 inFigure 10, are now provided but with their extreme end portions 47bared; they are so placed as to bring them in between the ears ortongues 45 and the end members 28 and thus rest against the member 28which, it is to be noted, is backed up on its under side and includingthose portions thereof that project beyond the end members 28 by themain body part of the sheet metal member 30. This relationship is alsowell shown in Figure 11-. The tongues 45 are now bent over and down uponthe insulated conductors 46, respectively, by any suitable means, andsunicient pressure is applied so that the insulated conductor issecurely clamped between the tongue and the sheet metal part 30, thusgiving this relatively heavy and stifl conductor a strong and durablemechanical anchorage and holding the bared ends 41 rigidly againstdisplacement or movement. The same operation also fixes the member 30 inposition which, as shown in Figure 11, becomes inescapablyinterlocked-with the member 26.

To these bared ends the bared end portions of the fine wire ends of thehigh voltage winding are now soldered, as indicated in Figure 10,preferably first taking a few turns of the fine wire about the bared endportions of the heavy wire. The resultant electrical connection is, dueto the strong mechanical anchorage of the heavy terminal wires 48,safeguarded against breakage, particularly during the subsequenthandling of the assemblage.

The assemblage may now be assembled to the core which, as above noted,may take the form of the shell type where the winding is to function ina transformer. the core being usually laminated and assembled out ofappropriately shaped laminations like the laminations 22 and 23 of whichthe lamination 22 provides the middle core leg 20, it being understood,of course, that the laminations 22 are assembled to the completedwinding structure alternately from the two end of the latter. Thus, onelamination 22 has its core leg 20 entered into the hollow bobbin fromone end thereof, while the next lamination 22 has its core leg 20entered into the bobbin from the opposite end of the latter, alamination 23 in each instance completing the individual magneticcircuits. The core may thus be built up to the desired extent,preferably snugly to fill up the space within the bobbin, suitablewedging means being employed, if desired, to secure tightness ofultimate interfitting. The core may thus be made to coact with the partsof the bobbin to hold the parts assembled. Thereafter, the completion ofthe transformer construction may be carried on in any suitable way, asby providing a suitable casing or mounting therefor.

Thus, it will be seen that there has been provided in this invention awinding support and winding structure and transformer construction inwhich the various objects hereinbefore noted, together with manythoroughly practical advantages are successfully achieved. It will beseen that the construction is simple, inexpensive, and thoroughlydependable in action and well adapted to meet the conditions of hardpractical use. Bobbin parts can be inexpensively stamped, as is alsotrue of the sheet metal part 30 of Figure 4,

and it will be seen that assembly thereof can be carried on quickly andinexpensively and with thoroughly reliable results.

As many possible embodiments may be made of the mechanical features ofthe above invention and as the art herein described might be varied invarious parts, all without departing from the scope of the invention, itis to be understood that all matter hereinabove set forth, or shown inthe accompanying drawing, is to be interpreted as illustrative and notin a limiting sense.

I claim:

1. A construction of the character described comprising a core with awinding thereon made of relatively small wire, said winding beingsupported by a bobbin made of insulating material having a sleeve-likeportion through which the core extends and about which is the windingand end members at the respective ends of the winding, said sleeve-likeportion having extensions beyond said end members, a sheet metal memberinterposed between said core and said sleeve and having bendableportions capable of being bent respectively over said extensions, tworelatively heavy insulated lead wires having their insulated endportions resting each against one of said extensions and each having oneof said bendable portions bent over the insulated end portion to clampit against the extension, for thereby anchoring said lead wires againstsaid extensions, the ends of said relatively small wire winding beingelectrically connected respectively to bared ends of said lead wires,the anchorage of which protects said relatively small wire ends againstbreakage and the insulation of said insulated lead wires against whichsaid bendable portions are bent preventing said sheet metal member fromshort-circuiting said two lead wires and from grounding either of themto said core.

2. A construction as claimed in claim 1 in which the extensions of saidsleeve-like portion have cut away parts through which the bendableportions of said sheet metal member extend from the core side of saidextensions to the opposite side thereof.

3. A construction as claimed in claim 1 in which said sleeve-likeportion of the bobbin is made up of a plurality of sheet-like members,said end members having polygonal openings therein through which saidsheet members extend, said sheet members and said end members havingrespectively interfitting parts, one of said sheet members being longerthan the spacing between said end members and projecting beyond each ofthe latter, thus to provide said extensions.

4. A construction as claimed in claim 1 in which said sleeve-likeportion of the bobbin is made up of a plurality of sheet-like members,said end members having polygonal openings therein through which saidsheet members extend, said sheet members and said end members havingrespectively interfitting parts, one of said sheet members being longerthan the spacing between said end members and projecting beyond each ofthe latter, thus to provide said extensions, said longer sheet memberhaving in its projecting ends slots for the passage therethrough oi. thebendable portions of said sheet metal member.

5. In construction of the character described, in combination, a bobbinmade of insulating material and comprising two axially spaced endmembers and an intervening sleeve-like portion for receiving on thelatter and between said end members a winding, said sleeve-like portionbeing extended beyond both of said end members to provide endextensions, and a conductorclamping element extending lengthwise of saidsleeve-like portion and having bendable end members related respectivelyto said end extensions and bendable relative to the latter to holditself in assembled relation to said sleeve-like portion.

6. In construction of the character described, in combination, a bobbinmade of insulating material and comprising two axially spaced endmembers and an intervening sleeve-like portion for receiving on thelatter and between said end members a winding, said sleeve-like portionbeing extended beyond both of said end members to form end extensions,each end extension hav ing a slot therein, and a sheet metal memberextending through said sleeve-like portion and provided with bendableparts extending through the slots in said extensions for clamping conductors against the latter and for holding said sheet metal member inplace.

7. In construction of the character described, in combination, a bobbinmade of insulating material and comprising two axially spaced endmembers and an intervening sleeve-like member for receiving on thelatter and between said end members a winding, a conductor connected tosaid winding, one of the members of said bobbin having exposed opposedend portions with a bendable conductor-clamping element extendingflatwlse thereagainst, said clamping element hav,- ing bendable endmembers respectively related to said opposed end portions andrespectively bent over the latter to hold itself assembled thereto, saidconductor being related to one of said bent elements and by it clampedand anchored against movement.

8. In construction of the character described, in combination, a bobbinmade of insulating material and comprising two axially spaced endmembers and an intervening sleeve-like portion for receiving on thelatter and between said end members a winding, said end members havingfour-sided apertures to form two pairs of opposed edges, saidsleeve-like portion comprising two pairs of sheet members one pair ofwhich is longer than the desired spacing between said end members andeach of said one pair having opposed recesses into which opposed edgesof said two end members are received to hold the latter in spacedrelation, the other pair of sheet members and said end members havinginterfitting parts in the form of interfitting tongues and recesses andthe contiguous edge portions of all of said sheet members havinginterfitting parts whereby said sheet members are mutually supportedagainst movement inwardly toward the axis of said bobbin, said endmembers holding said sheet members against movement outwardly from saidaxis, one of said sheet members extending at both ends beyond said twoend members to form two end extensions, two relatively heavy terminalconductors having electrical connection with the ends of said winding,and a single bendable clamping means extending along said extended sheetmember to the respective ends thereof and having clamping means at itstwo ends for respectively clamping the ends of the extended sheet memberand said two heavy terminal conductors.

9. In construction of the character described, in combination, a bobbinmade of insulating material and comprising two axially spaced endmembers and an intervening sleeve-like portion for receiving on thelatter and between said end members a winding, said end members havingfour-sided apertures to form two pairs of opposed edges, saidsleeve-like portion comprising two pairs of sheet members one pair ofwhich is longer than the desired spacing between said end members andeach of said one pair having opposed recesses into which opposed edgesof said two end members are received to hold the latter in spacedrelation, the other pair of sheet members and said end members havinginterfitting parts in the form of interfitting tongues and recesses andthe contiguous edge portions of i all of said sheet members havinginterfitting parts whereby said sheet members are mutually supportedagainst movement inwardly toward the axis of said bobbin, said endmembers holding said sheet members against movement outwardly from saidaxis, at least one 01' said sheet members being extended at at least oneend beyond an end member, a relatively heavy terminal conductor inelectrical connection with said winding, and a sheet metal memberresting against said extended sheet member and having two spacedclamping portions bendable against the opposite face of said extendedsheet member, at least one of said bendable portions engaging theextension of said sheet member and also clamping said terminal conductorthereto.

10. In construction of the character described, in combination, a coreand a winding thereabout, a sheet-like member of insulating material anda sheet metal member interposed between said winding and said core andboth extending beyond an end of said winding, said sheet metal memberbeing between said sheet member and said core, and a terminal conductorfor said winding and in electrical connection with the latter, saidterminal conductor being clamped in position by a bent-over portion ofsaid sheet metal member and said bent-over portion coacting to hold saidsheet metal member against movement relative to said core.

11. In construction of the character described, in combination, awinding support of insulating material comprising two axially spaced endmembers between which the winding is received and an insulating memberextending between said end members for underlying the winding, saidlastmentioned member being extended beyond both of said end members toprovide end extensions, and a sheet metal member underlying said memberand its end extensions and having portions bent over said endextensions, and a conductor, one of said sheet metal portions engagingand clamping said conductor.

'12. In construction of the character described, in combination, awinding support of insulating material comprising two axially spaced endmembers between which the winding is received and an insulating memberextending between said end members for underlying the winding, aconductor, and a sheet metal member underlying said mem her and havingend portions extending beyond said end members, said end portions ofsaid sheet member being bent relative to said bobbin to hold 40 itselfassembled thereto and at least one of said portions engaging andclamping said conductor.

13. In construction 0! the character described, in combination, awinding support of insulating material comprising two axially spaced endmembers between which the winding is received and an insulating memberextending between said end members for underlying the winding, saidlastmentioned member being extended beyond both of said end members toprovide end extensions, and a sheet metal conductor-securing memberunderlying said member and its extensions and having bent end portionsoverlying said extensions for' holding said sheet metal member and saidinsulating member together.

14. In construction of the character described, a sub-assemblycomprising a bobbin made of insulating material and comprising twoaxially spaced end members and an intervening sleevelike portion forreceiving on the latter and between said end members a winding, saidsleevelike portion being extended beyond both of said end members toform end extensions, and a sheet metal member extending through saidsleeve portion and provided with bendable parts at its ends respectivelyoverlying said end extensions for holding said sheet metal member inplace and for clamping a conductor by at least one of said bendableparts.

15. In construction of the character described, in combination, awinding support of insulating material comprising two axially spaced endmembers between which the winding is received and an insulating memberextending between said end members for underlying the winding, saidmember being extended to expose at least two edges thereof, a lead wire,and a sheet metal member lying along one face of said extended memberand having clampingportions extending about said edges to the other facethereof for holding itself assembled .to said extended member and forclamping said conductor in position.

, JOHN C. J OOST.

